Forget the easy old joke—the elevator overdouser; the Pepe le Pew—that everyone who talks (or writes) about men's fragrance always seems to round back to. In my experience, it's usually women whose liberal spritzes tend to make your eyes water. Besides, anyone who reaches for a mental gas mask the second she hears the word cologne obviously has not encountered Gaspard Ulliel. Picture a younger, more intellectual Keanu: iron-jawed, dressed by his old friend Hedi Slimane, and recently chosen by none other than Martin Scorsese to star in a short film for Chanel's latest men's scent, Bleu de Chanel. (Yes, even Scorsese directs fragrance "films" these days.) "Fragrance goes beyond fashion," Ulliel said recently, over fresh-squeezed jus d'orange at Paris' Hotel Ritz. "It's part of your identity. It's very important to have a special smell." Okay, sure, you're thinking, fragrance is paying the man's bills; of course he's a believer. But Ulliel is also a straight, seemingly secure Frenchman who loves artsy auteur Wong Kar-Wai, truffles, and Ingmar Bergman's ultranoir Persona; he'd wear the stuff even if it weren't in his contract. And pity the poor mademoiselle who catches a whiff of Bleu's citrusy cedar blend under that collar. She's likely to cash in her chips at first sniff.

Call me scentimental, but I'm with Ulliel on this one. A man's fragrance is important. If thoughtfully chosen and discreetly applied—yes, two big ifs—it's a game-changing breath of pure possibility, hinting at everything about its wearer that doesn't necessarily meet the eye. If he's a suit, a hint of smoky vetiver suggests his less straitlaced side; if he's a nerd, it portends a not immediately obvious level of sophistication. If he's old faithful, it's a puff of healthy mystery, a reminder of the attraction he still holds to the wider world (and, even better, that's he's cleverly maintaining for you). If, on occasion, this little olfactory sleight of hand turns out to be false advertising, the male equivalent of Spanx, c'est la vie.

Still, the whys and wherefores of men's fragrance remain something of a mystery: Who, besides hot French pitchmen, wears it? And what do they wear? There seemed to be only one way to get to the bottom of it: ELLE would assemble a crack team to gamely track the scent-buying and -wearing habits of three broad stripes of the modern male: finance men, hipsters, and sports enthusiasts. In other words, we went out and smelled a bunch of guys. Wildly unscientific though our research may have been, the results could change what you think about Gaspards and Pepes alike.

Fellow ELLE editor April Long and I embark upon our odyssey, appropriately enough, at Ulysses, the after-work watering hole of Wall Street day traders. We're just getting our sea legs in its packed outdoor courtyard—starchy blue and white button-downs as far as the eye can see—when I receive a panicky text from Celine Barel.

Barel has been recruited to lend a thin veneer of legitimacy to our team. As a nose at the fragrance house International Flavors & Fragrances (IFF) who has whipped up, among others, Coach Poppy, Beckham Signature Story for Him, and, most recently, the haute-vanilla Jo Malone Vanilla & Anise, she's the only one of us who truly knows what she's talking about. "Where R U?" she writes. "I'm afraid the bankers think I'm a hooker trying to pick up!" They wish. Barel, it turns out, is from the French Riviera—she grew up in Grasse, the birthplace of French perfume and, it appears, of sexy French girls—and is wearing a bright green wrapdress and shiny, dangly earrings. By the time we locate her, men on all sides are eyeing her vulturously.

Colin, an early-thirties redhead, is already angling for her attention, so I not-so-subtly shove Barel in his direction. "Hi, would you mind if my friend, um, smells you?" A blush leaps from his French-blue collar to his hairline. "Sure?" he squeaks. Celine dutifully inhales: the end-of-day remnants of Chanel Allure Homme. "The raw materials are good," she says approvingly. (Later, she'll elaborate: "It's about the brand itself: the gatekeeper of good taste. You know you're buying quality, and it's a safe bet because it's classic.")

But not all Wall Streeters are as amenable as Colin. When we descend upon the rest of the herd, our nostrils aquiver, we seem to trip some invisible wire in their social order. Apparently men are no more thrilled to be aggressively sniffed by a stranger—even a Natalie Portman look-alike with zee French accent—than women would be. And is it just my hypersensitive sexism-o-meter, or are they miffed by women who approach, rather than demurely waiting to be approached? One table actually evacuates as we head their way. I look at April, flummoxed. "Hey, it's not my story," she says with a smirk. "Thank God."

Several hours later, with a fair amount of legwork and humiliation, we get this much: three votes for various Burberry fragrances, and one each for Banana Republic Classic, Dolce & Gabbana The One Gentleman, Drakkar Noir, and YSL L'Homme. The trendier guys—narrow ties, slimmer trousers, more apparent hair product—seemed to choose trendier scents: Prada Amber Pour Homme, Jean Paul Gaultier Le Male (fascinating, given its, um, wildly unbankerish male torso–shaped flacon). All in all, almost everyone we talked to was a regular scent-wearer. They were terribly loyal, sticking to a single scent for as long as 10 years, and even Barel was surprised to learn how many of them purchased the stuff for themselves (mostly impulse buys in department stores). "All their brands are classic, status oriented—nothing bling-bling," she said. "They're safe, not edgy, and well-rounded...rich." Amazingly, only two of the men we spoke with professed to wear no fragrance at all. And there was not an overspritzer in the crowd.

"What is this...heep-ster?" Barel wants to know, as we jump in a taxi headed for the Lower East Side, the Manhattan habitat of this pervasive breed. We tell her she'll know it when she sees it; trouble is, upon arrival, there isn't an ironic T-shirt or skinny tie in sight. We hit, in rapid succession, Pianos, Cake Shop, and Motor City, three foolproof man-boy bars. Though they've left evidence in their wake—band flyers, Sharpie-scrawled bathrooms—we catch nary a waft of hipster.

Finally, we spot a twentysomething slinging a guitar case, skinny jeans hanging precariously from his jutting hipbones. "Look," April whispers, pointing at the clutch of telltale plaid in the bar where he's headed. "There they are." By now we have learned that the market research/intrepid girl-reporter stance—eager expression, poised notepad—is not one any guy wants to see coming at him after dark. We fake nonchalance at the bar.

But our first three subjects smell of little more than Ivory soap (and number four would have benefited from a bar or two). Among them, we record one single, dusty bottle of Le Male owned "for, like, 10 years" and a vote for Old Spice deodorant.

Luckily, Barel is deep in conversation with what looks to be a boy-band member. This turns out to be Zack Weber, an earnest young singer-songwriter who—even before I've gone home and googled him like a salivating middle-schooler—has the mournful emo beauty and floppy hair that spell YouTube star.

Weber and his bandmates happily cop to being fragrance wearers, but their tastes are all over the place: the underexposed Desire by Alfred Dunhill, another Gaultier, Fleur du Male. Several have bought into music-oriented or bad-boy advertising, collecting Burberry The Beat for Men, Diesel's fist-shaped Only the Brave, or "the Justin Timberlake one," i.e., Givenchy Play. And then there's the Marc Jacobs–besuited hipster lawyer—odd man out not just in this bar, but in this neighborhood—who informs us he wears Dior Homme and the ultraniche, super-expensive Frédéric Malle Iris Poudre. "I tend to like the male equivalent of a powdery aldehyde," he informs us. Righto.

Let's be honest: It's a little off-putting when a man's fragrance lexicon is that developed. We want them to wear it, not major in it. Luckily, most guys we spoke to were limited to two words: sexy and musk. "In America, every time a perfumer gets a fragrance brief, the first word is clean," Barel says. Here, she explained, sexy equals clean, which is both musky—skinlike—and fresh, meaning citrus or grass or water smells, "just out of the shower," she says. "In this country, you're out of your mind if you don't take a shower before a date." Whereas in France, her compatriots are "more into the moment" and, pre-date, more likely to splash on a smell rather than scrubbing it off. Their first idea of sexy is "warm"; thus, the earthy, spicy cumin that's front and center in a Europe-targeted men's scent such as Cartier Déclaration would smell vaguely "dirty" to most Americans, i.e.: charming to the hipster, who fancies himself off the beaten track; slightly riskier to the banker; and, as we soon learn, utter poison to the American sportsman.

The Sports Fan

Two days after our Lower East Side expedition, our trio steps off the D train in upper Manhattan and is instantly swept up in a wave of navy-and-white-striped jerseys headed toward the ultimate cathedral of mandom, the luxe new Yankee Stadium.

Fragrant does not even begin to describe this place. It is redolent with good old-fashioned, gloriously caloric Americana: barbecue sauce, buttered popcorn, garlic fries, the yeasty waft of 20,000 beers. Thing is, the scent parade stops abruptly at the snack bars. On the emerald field, I can only presume Derek Jeter is wearing one of the six scents he's fronted for Avon—sadly, we can't get close enough to tell—but in the stands, his fans are stubbornly scent-free. A courtly college football player turned businessman beside us insists the only thing he's ever sprayed on himself is Right Guard. Even on dates? "Nope." In high school? "Nah." But what if it offered an advantage with the ladies? "I guess I'm not that worried about that." He shrugs his sprawling boulder-shoulders, oozing unbridled testosterone, as if to say, "Why would I be?" Point taken.

We corner a suburban-looking foursome drinking beers outside of Nathan's. They glance at one another and scoff at the mere suggestion: "Fragrance? You mean, like, cologne? No way." Admitting they wore the stuff would clearly be grounds for expulsion from the man club.

"I have a lot of them," ventures one.

"Yeah, but you haven't worn 'em since you got married in 1998!"

Determined, we forge ahead. But in the hot dog line, nothing. In the beer line, nothing. In the cheese fries line, nothing. In the fried dough line, nada. Finally, around our 3,500th calorie and Jeter's second home run, Barel's nose begins to twitch. "Givenchy Play!" she gasps. "Diesel Fuel for Life!" We've snuffled into the vapor trail of two guys whose Yankee caps and T-shirts are clearly fresh from the stadium gift shop. Australians, they landed at JFK four hours earlier. And between them, these two could open a Sephora. They like David Beckham scents for day; Gucci Envy for dates; for a sure bet, Joop! "Our friends get a lot of action with that," one says, leering hopefully at Barel.

But we're far more taken with two navy officers who are cheerfully submitting to photo ops with passersby, their white uniforms positively sparkling in the fluorescent light. Yes, ma'am, these guys are man enough to wear fragrance: patriotic Polos and Hilfigers, for the most part—also popular, they report, with the other guys in their unit. These manly men totally get it: What easier escape from the male uniform—whether it's government issue or standard blue-shirt-and-khakis—than the small, private effort of a quick spritz? And take it from us: They use just the right amount.